Co-occurring mutations in CLL affected GNA13, KMT2D, LRP1B, MUC16, and SPEN. Additionally, co-occurring mutations in B-cell lymphomas were found in CSMD3 (grade I follicular lymphoma), EP300 (DLBCL), FAT1 (DLBCL), HIST1H1E (grade I follicular lymphoma), KMT2D (DLBCL), MCL1 (grade IIIa follicular lymphoma), MSH6 (grade IIIa follicular lymphoma), MYC (DLBCL), PIM1 (grade I follicular lymphoma), RNF213 (DLBCL), and SIN3A (grade IIIb follicular lymphoma). The gene discussed is SPEN; the disease is follicular lymphoma.